A New "A" Battery

Radio Record, Volume II, Issue 8, 7 September 1928, Page 29

A New "A" Battery

NEW type of A battery accumulator has been invented by a Portuguese Jesuit. As far as can be gathered, the Almeida accumulator resembles the existing ones in so far as it has its positive and negative plates with a container and electrolyte, but it is much lighter, while the container itself can be made from a cheaper material than hitherto. The electrodes themselves are particularly interesting, the positive plate being a mixture of what may be termed a "passive" conductor and a small proportion of silver, the latter acting as a catalytic agent. Not Expensive. GIN OB the quantity of silver used is quite small, there is no fear cf great expense entering into the cost of manufacture. Expressing it in simple language, we may say that as far as chemical reactions. are concerned the silver only works by its "presence," and is not "consumed" in the actual sense of the word. The negative electrode is essentially, but not wholly, metallic zine, and the two electrodes work in an electrolyte made up from a solution of chloride of zine with salts of the same metal (such as zinc bromide). The accumulator is remarkable in that as soon as it is assembled it can be charged and discharged immediately without any of the usual process of formation, and this undoubtedly is a distinct advantage. Examining this process, we find that what has been termed the passive conductor of the positive plate, e.g., graphite, generally works with the silver (reduced to powder) to facilitate the action that is being developed by the catalytic agent during the process of charge. AS soon as a charging current flows electrolysis begins, first the bromide and then the chloride of zinc being decomposed. Cannot "Sulphate." FOR the purposes of explanation, the ‘inventor splits up the actual charge and discharge periods into three phases. Sulphation, that bugbear of the acid types of accumulators, unless due care and attention is paid to them is nonexistent in the Almeida accumulator. Parasitic discharges do not take place in the positive plate, since it only consists of a passive conductor and a catalytie agent; while, since the negative plate is practically metallic zine resting in a solution of chloride or bromide of zine, no internal reactions occur. In consequence of this important feature it does not matter-in what state of charge or discharge the accumulator may be left. It can be retained in that condition for an indefinite period without discharging itself or losing any of its energy. These features, coupled with the fact that.numbers of tests have established a figure of 98 per cent. for the accumulator efficiency, calculated on the usual basis, should serve to awaken a good deal of thought, and further developments are awaited with interest to see how far theory and practical laboratory experiment can be borne out when

it comes to be tackled from the point of view of bulk manufacture. Large Capacity. ADDED to this, weight for weight, the capacity is ten times greater ; or, conversely, capacity for capacity, the weight is only one-tenth of the average weight for the other two types.